The crash site has been blocked to recreational boat traffic while the agency investigates, the Coast Guard official said.

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While the males often hang out near the harbour within easy view from shore, the females generally live further back in the protected slough, where there is less boat traffic.

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Shark and Clark Islands, located off the harbourside suburb of Darling Point and Rose Bay respectively, became dedicated recreational areas as early as the 1870s and are now great places to watch the boat traffic in Sydney Harbour.

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The area remained an unnavigable bog, forcing traders to drag their boats through the mud until 1848, when William Butler Ogden, the mightiest industrialist in the Midwest, backed the first canal that allowed boat traffic to sail straight through.

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There's endless amounts of boat traffic.

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The demonstrators accuse Norte Energia of damming the final canal of the river without having solved the matter of how to move boat traffic from one side of the cofferdam to the other, as required by the Installation License issued by Ibama.

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Traffic problems had led to delays and the plan was changed to leave the pontoons in Ipswich, so that the boat could be picked up and delivered first.

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